CONSERVATION
IUCN Redlist category Near Threatened (IUCN 2020)
Rationale for redlist categorization Troides riedeli has been assessed as Near Threatened. This species has a very restricted extent of occurrence of just under 5,000 km? on Yamdena and Sera Islands in the Tanimbar Island group of Indonesia. Very little information is available for this species on its habitats, ecology and specific distribution; very little is known about its population status. In the past, the species was not thought to be rare but more up-to-date data is unavailable. Threats appear to occur on the islands where the species is found: data from Global Forest Watch shows highest forest loss since 2001 in coastal, low lying areas of Yamdena Island, which is where the species is most likely to occur. There are no data to suggest whether the species can cope with habitat loss and can occur in more open habitat; there are also no data on how any forest loss may affect its larval food plant. Assuming here, using a precautionary approach, that this forest loss is leading to a continuing decline in the extent and quality of the species' habitat, we assess the species as Near Threatened due to meeting the area threshold under B1 and the continuing decline criteria under subcriterion b(iii). New data are required to verify this assessment in future. (IUCN 2020)
Threat category Species mortality (IUCN 2020)
Cause of stress Intentional use (species is the target) (IUCN 2020)
Described Threats The species is listed on CITES Appendix II together with the genera Ornithoptera and Trogonoptera , with the exception of O. alexandrae which is listed on Appendix I. Recently traded individuals appear to come mostly from captive or ranched populations (CITES 2015). Butterfly ranching is generally thought of as a sound, economically viable and sustainable rural industry (Wambi 1996, Hanscom 1993, Burrows 2003 in Small 2007). However, there are concerns that butterfly ranching may not be as sustainable in some countries as it is often perceived to be (e.g., Papua New Guinea; Small 2007). This is based on a lack of data and species monitoring to assess the status of butterfly populations, and for many species, such monitoring is fraught with difficulty due to inaccessibility of their habitat (Small 2007). New and Collins (1991) noted that trade is extremely difficult to monitor because transportation of unpinned specimens is easy, especially of comparatively low value species which may instead be traded at high volumes. It has been stated that overcollecting seldom becomes a threat to butterflies, due to the reproductive capacity of insects and the difficulty in capturing significant numbers of the population (Pyle and Hughes 1978, in Parsons 1992). However, where birdwing butterflies are highly specific to host plants and where density of these hosts plants limits population size, collection in conjunction with habitat loss could have significant impacts on the species or subpopulations.
For most birdwing butterflies, habitat loss is by far the most important threat; data from Global Forest Watch shows highest forest loss since 2001 in coastal, low lying areas of Yamdena Island, which is where the species is most likely to occur (Hansen et al. 2013). There are no data to suggest whether the species can cope with habitat loss and can occur in more open habitat; there are also no data on how any forest loss may affect its larval food plant. (IUCN 2020)
Commercial use Butterflies are mostly traded dead for the curio market (Collins and Morris 1985, New and Collins 1991). Between 1998 to 2007, 306,000 butterflies were traded from Southeast Asia, with 13,000 of these being wild-caught (Nijman 2010). There is a distinct shift towards ranched and captive-bred individuals in trade from 2003 onwards; in 1985, it was reported that globally less than 10% of trade was in ranched individuals (Collins and Morris 1985). Altogether at least 34 different species were recorded in trade, most of which belonged to the birdwing butterflies ( Troides and Ornithoptera ; Nijman 2010). It should be noted that trade in butterflies may be underreported, because of difficulties monitoring. New and Collins (1991) noted that trade is extremely difficult to monitor because transportation of unpinned specimens is easy, especially of comparatively low value species which may instead be traded at high volumes.
Birdwings can fetch high prices on the market. For example, butterfly collectors have paid high prices for birdwing butterflies of this genus: a pair of Ornithoptera meridionalis was reported to have fetched USD 3,400 in Germany (Melisch and Schutz 2000). Reported prices for Troides are however much lower. For example, a more recent pricing was around $85 per pair of T. hypolitus , around $15 per individual of T. helena and between $43 and $85 per pair of T. haliphron (Putri 2016). This species is listed on Appendix II of CITES. Recent data from the CITES Trade database show, that since 2000 and 2015 just short of 1,000 individuals were exported from Indonesia, all from captive or ranched populations (UNEP-WCMC 2012, CITES 2015). (IUCN 2020)
Applied conservation actions In a status assessment of the world's swallowtails, carried out in 1985, the species was not thought to be threatened (Collins and Morris 1985). In 1991, New and Collins suggested work to fully integrate swallowtails into national conservation planning in Indonesia (1991), primarily for those species which were identified as threatened at the time - however, any such work would likely have benefited other birdwing species in the country. The species is listed as protected in Indonesia (Collins and Morris 1985, President of the Republic of Indonesia 1999). It was, however, suggested that careful monitoring may be required for this species, as well as habitat protection (Collins and Morris 1985) since any habitat disturbance leading to adverse impacts on the species may lead to a higher threat listing for this species. These recommendations still hold true: specifically, field data are required on the distribution, ecology and habitats of this species. (IUCN 2020)
REFERENCES
- CITES. 2015. CITES Trade Data Base. Available at: http://trade.cites.org/.
- Collins, N.M. and Morris, M.G. 1985. Threatened Swallowtail Butterflies of the World. The IUCN Red Data Book. IUCN, Gland and Cambridge.
- Hanscom, T. 1993. Setting hearts aflutter: little butterflies take wing as big business. The Rotarian 163: 16-19.
- Hansen, M.C., Potapov, P.V., Moore, R., Hancher, M., Turubanova, S.A., Tyukavina, A., Thau, D., Stehman, S.V., Goetz, S.J., Loveland, T.R., Kommareddy, A,. Egorov, A., Chini, L., Justice, C.O. and Townshend, J.R.G. 2013. High-resolution global maps of 21st-century forest cover change. Science 342: 850-853.
- IUCN. 2020. The IUCN Red List of Threatened Species. Version 2020-3. Available at: www.iucnredlist.org. (Accessed: 10 December 2020).
- Melisch, R. and Schutz, P. 2000. Butterflies and beetles in Germany. Traffic Bulletin 18: 91-93.
- New, T.R. and Collins, N.M. 1991. Swallowtail butterflies: an action plan for their conservation. International Union for Conservation of Nature and Natural Resources/Species Survival Commission Lepidoptera Specialist Group, Gland, Switzerland.
- Nijman, V. 2010. An overview of international wildlife trade from Southeast Asia. Biodiversity and Conservation 19(1101-1114).
- Parsons, M.J. 1992. The butterfly farming and trading industry in the Indo-Australian region and its role in tropical forest conservation. Tropical Lepidoptera 3(Suppl. 1): 1-31.
- President of the Republic of Indonesia. 1999. Nomor 7 Tahun 1999 Tentang Pengawetan Jenis Tumbuhan dan Satwa. Peraturan Pemerintahan Republik Indonesia.
- Putri, I.A.S.L.P. 2016. Handicraft of butterflies and moths (Insecta: Lepidoptera) in Bantimurung Nature Recreation Park and its implications on conservation. Biodiversitas 17(2): 823-831.
- Pyle, R.M. and Hughes, S.A. 1978. Conservation and Utilization of the Insect Resources of Papua New Guinea. Wildlife Branch, Department of Natural Resources, Port Moresby.
- Small, R.D.S. 2007. Becoming unsustainable? Recent trends in the formal sector of insect trading in Papua New Guinea. Oryx 41(3): 386-389.
- UNEP-WCMC. 2012. Review of butterflies from Asia and Oceania subject to long-standing positive opinions. Prepared for the European Commission Directorate General E - Environment ENV.E.2. ? Development and Environment. UNEP-WCMC, Cambridge.
- Wambi, D. 1996. Birds, bugs and butterflies. New Guinea Insight 6: 5-9.